A piston of this kind, generally known as a light piston, is described and illustrated in DE-GM 71 08 800. In this known form of piston the filler piece is formed by pressing-in a section of the wall of the hollow body overlapping the free end of the filler piece to form a flange against the end face of the filler piece. However, the filler piece is not held securely enough axially between the bottom of the cavity and the flange, because first, once the flange has been formed it gives to some extent and second, owing to the relatively long curve that arises when forming the flange, the flange is like a relatively long lever arm whose axial torsional strength is relatively small. As a result of this the object of prestressing the filler piece against the bottom of the cavity using tension exerted by the flange cannot be achieved.
In DE-OS 38 04 424 it has already been proposed to secure the filler piece in the hollow body by additional indentations which are located in the central longitudinal region of the piston, and are formed by indenting the wall of the hollow body into recesses in the filler piece located beneath it. In addition, at the free end of the piston a section of the wall of the hollow body axially overlapping the filler piece is rolled-in against the end face of the filler piece, with the primary object of protecting the end wall of the lighter, and as a rule softer, material from cavitation. In this known form of piston it is true that the filler piece is held stably in the hollow body, but there is the danger of stress cracking and of fracture in the region of the indentations, especially in the case of a piston with a relatively thin cavity wall.